Prostaglandin and PMSG administration at different times during an estrus synchronization protocol in buffalo.

The aim of this study was to optimize the treatment for oestrus synchronization based on PRID+PMSG+PGF in Italian Mediterranean buffaloes in order to apply AI. The animals (n=93) at 160.8±114.3 days of lactation were divided in two homogeneous groups and a progesterone releasing intravaginal device (PRID) was inserted for 10 days in all subjects. Buffaloes in Group A (n=47) received an i.m. injection of 1000 IU of PMSG and 0.15 mg of cloprostenol on day 7 (Day 0= day of PRID insertion), whereas animals in Group B (n=46) received the same injections of PMSG and PGF on day 10 (day of PRID removal). The AI was carried out at 72 and 96 hours after PRID removal using frozen/thawed semen of progeny test bulls. The pregnancy diagnosis was performed on day 26 after the first AI by an ultrasound sector scanner with a 7.5 Mhz rectal linear probe and confirmed by a gynaecologic visit on day 45. The data were analysed by chi square test. No significant differences were observed in terms of pregnancy rate on day 26 between the groups (48.9% and 32.6% respectively in group A and B). On the contrary, a significant (P